1. Field of the Invention
The present invention relates to flow divider valves for hydraulic systems and more particularly to flow divider valves which are adapted to divide the flow from a single pump into two flows to be supplied to independent hydraulically operated devices.
2. Description of the Prior Art
Loading vehicles such as fork lifts are generally provided with a plurality of independent, hydraulically operated devices. A fork lift vehicle, for example, has a fork lifting device, a fork tilting device, a power steering device, a brake booster, and a clutch releasing booster. In these vehicles, it is desirable that the hydraulically operated devices be supplied with hydraulic flow from a common or single pump so as to reduce the cost and the weight of the vehicle. In addition, it is desirable that the hydraulic circuits of the devices be designed as open hydraulic circuits so as to reduce the cost and weight of the vehicle.
In order to supply the hydraulic flow from the common pump to several hydraulically operated devices, flow divider valves have been developed to divide the flow from the pump into two flows to be supplied to separate hydraulic devices.
In these conventional flow divider valves, however, a sudden, large change in hydraulic pressure, or flow volume, in an inlet port due to the operation of one of the hydraulically operated devives upstream of the flow divider valve, causes a sudden, large change in the flow volume in the outlet ports. This change in the flow volume is undesirable as it adversely affects operation of hydraulic devices downstream from the flow divider valve, such as a brake booster or clutch releasing booster.
Change of flow volume to the brake or clutch releasing boosters causes a shock on the brake or clutch pedal. Especially in the clutch releasing booster, the change of flow volume may cause engagement of the vehicle clutch. This is very dangerous.
Accordingly, it is the object of the present invention to solve the above drawbacks of conventional flow divider valves.